#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @Date    : 2020-08-29 23:17:15
# @Author  : Zuo Zhongfei (zuozhongfei@126.com)
# @Link    : www
# @Version : $Id$

import os
import sys
import pygame
from bullet import Bullet
from alien import Alien
from time import sleep
from button import Button

def check_keydown_events(event, ship, ai_settings, screen, bullets,stats):
    # 响应按下按键
    if event.key == pygame.K_RIGHT:
        ship.moving_right = True
    elif event.key == pygame.K_LEFT:
        ship.moving_left = True
    elif event.key == pygame.K_UP:
        ship.moving_up = True
    elif event.key == pygame.K_DOWN:
        ship.moving_down = True
    elif event.key == pygame.K_SPACE:
        fire_bullet(ai_settings, screen, ship, bullets)
    elif event.key == pygame.K_q and event.key == pygame.K_COMMA:
        sys.exit()
    elif event.key == pygame.K_p:
        start_game(stats, ai_settings)


def check_keyup_events(event, ship):
    # 响应松开按键
    if event.key == pygame.K_RIGHT:
        ship.moving_right = False
    elif event.key == pygame.K_LEFT:
        ship.moving_left = False
    elif event.key == pygame.K_UP:
        ship.moving_up = False
    elif event.key == pygame.K_DOWN:
        ship.moving_down = False


def check_events(ai_settings, screen,stats,play_button, ship, bullets,sb):
    # 响应键盘和鼠标事件
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            sys.exit()

        elif event.type == pygame.KEYDOWN:
            check_keydown_events(event, ship, ai_settings, screen, bullets,stats)

        elif event.type == pygame.KEYUP:
            check_keyup_events(event, ship)
        elif event.type == pygame.MOUSEBUTTONDOWN:
            mouse_x,mouse_y = pygame.mouse.get_pos()
            check_play_button(stats,play_button,mouse_x,mouse_y,ai_settings,sb)

def check_play_button(stats,play_button,mouse_x,mouse_y,ai_settings,sb):
    """在玩家点击play按钮时开始新游戏"""
    button_clicked = play_button.rect.collidepoint(mouse_x,mouse_y)
    if button_clicked and not stats.game_active:
        start_game(stats,ai_settings)

        # 重置分数和飞船数
        sb.prep_score()
        sb.prep_ships()

def start_game(stats,ai_settings):
    """开始游戏"""
    stats.game_active = True
    # 游戏开始时，隐藏鼠标
    pygame.mouse.set_visible(False)
    ai_settings.initialize_dynamic_settings()
    stats.ships_left = ai_settings.ship_limit


def update_screen(ai_settings, screen,stats,sb, ship,aliens, bullets,play_button):
    # 每次循环时重绘屏幕
    screen.fill(ai_settings.bg_color)

    # 在飞船和外星人后面重绘所有子弹
    for bullet in bullets.sprites():
        bullet.draw_bullet()

    # 在指定的位置绘制飞船
    ship.blitme()

    aliens.draw(screen)

    # 显示得分
    sb.show_score()

    # 如果游戏处于非活跃状态，就绘制play按钮
    if not stats.game_active:
        play_button.draw_button()

    # 让最近绘制的屏幕可见
    pygame.display.flip()


def update_bullets(ai_setting,screen,ship,aliens,bullets,stats,sb):
    """更新子弹的位置，并删除已经消失的子弹"""
    # 更新子弹的位置
    bullets.update()

    # 删除消失的子弹
    for bullet in bullets.copy():
        if bullet.rect.bottom <= 0:
            bullets.remove(bullet)

    check_bullet_alien_collisions(ai_setting,screen,ship,aliens,bullets,stats,sb)


def check_bullet_alien_collisions(ai_settings,screen,ship,aliens,bullets,stats,sb):
    # 检测是否有子弹击中了外星人，如果有就删除相应的子弹和外星人
    collisions = pygame.sprite.groupcollide(bullets, aliens, True, True)
    if collisions:
        for alien in collisions.values():
            stats.score += ai_settings.alien_points
            sb.prep_score()
            check_high_score(stats,sb)

    # 新增的这行代码遍历编组bullets 中的每颗子弹，
    # 再遍历编组aliens 中的每个外星人。
    # 每当有子弹和外星人的rect 重叠时，
    # groupcollide() 就在它返回的字典中添加一个键-值对。
    # 两个实参True 告诉Pygame删除发生碰撞的子弹和外星人。
    # （要模拟能够穿行到屏幕顶端的高能子弹——消灭它击中的每个外星人，
    # 可将第一个布尔实参设置为False ，并让第二个布尔实参为True 。
    # 这样被击中的外星人将消失，但所有的子弹都始终有效，直到抵达屏幕顶端后消失。

    if len(aliens) == 0:
        bullets.empty()
        ai_settings.increase_speed()
        create_fleet(ai_settings, screen, ship, aliens)

def fire_bullet(ai_settings, screen, ship, bullets):
    """如果还没有达到限制就发射一颗子弹"""
    # 创建一颗子弹，并将其加入到编组bullets中
    if len(bullets) < ai_settings.bullet_allowed:
        new_bullet = Bullet(ai_settings, screen, ship)
        bullets.add(new_bullet)

def create_fleet(ai_settings,screen,ship,aliens):
    """创建外星人群"""
    # 创建一个外星人，并计算一行可以容纳多少个外星人
    # 外星人间距为外星人宽度
    alien = Alien(ai_settings,screen)

    number_aliens_x = get_number_aliens_x(ai_settings,alien.rect.width)
    number_rows = get_number_rows(ai_settings,ship.rect.height,alien.rect.height)

    # 创建外星人群
    for row_number in range(number_rows):
        for alien_number in range(number_aliens_x):
            # 创建一个外星人并加入当前行
            create_alien(ai_settings,screen,aliens,alien_number,row_number)


def get_number_aliens_x(ai_settings,alien_width):
    """计算每行可容纳多少个外星人"""
    available_apace_x = ai_settings.screen_width - 2 * alien_width
    number_aliens_x = int(available_apace_x / (2*alien_width))
    return number_aliens_x

def create_alien(ai_settings,screen,aliens,alien_number,row_number):
    """创建一个外星人并将其放在当前行"""
    alien = Alien(ai_settings,screen)
    alien_width = alien.rect.width
    alien.x = alien_width+2*alien_width*alien_number
    alien.rect.x = alien.x
    alien.rect.y = alien.rect.height + 2 * alien.rect.height * row_number
    aliens.add(alien)

def get_number_rows(ai_setting,ship_height,alien_height):
    """计算屏幕可容纳多少行外星人"""
    available_space_y = (ai_setting.screen_height - (3*alien_height)-ship_height)
    number_rows = int(available_space_y / (2*alien_height))
    return number_rows

def update_aliens(ai_settings,stats,screen,ship,aliens,bullets,sb):
    """“检查是否有外星人位于屏幕边缘，并更新整群外星人的位置"""
    check_fleet_edges(ai_settings,aliens)
    aliens.update()

    if pygame.sprite.spritecollideany(ship,aliens):
        print("Ship hit!!!")
        ship_hit(ai_settings,stats,screen,ship,aliens,bullets,sb)

    # 检查是否有外星人到达屏幕底端
    check_aliens_bottom(ai_settings,stats,screen,ship,aliens,bullets,sb)


def check_fleet_edges(ai_settings,aliens):
    """有外星人到达边缘时采取相应的措施"""
    for alien in aliens.sprites():
        if alien.check_edges():
            change_fleet_direction(ai_settings,aliens)
            break

def change_fleet_direction(ai_settings,aliens):
    """将整群外星人下移，并改变他们的方向"""
    for alien in aliens.sprites():
        alien.rect.y += ai_settings.fleet_drop_speed
    ai_settings.fleet_direction *= -1

def ship_hit(ai_settings,stats,screen,ship,aliens,bullets,sb):
    """响应被外星人撞到的飞船"""
    if stats.ships_left > 0:
        # 将ships_left减1
        stats.ships_left -= 1

        # 更新飞船数
        sb.prep_ships()

        # 清空外星人列表和子弹列表
        aliens.empty()
        bullets.empty()

        # 创建一群新的外星人，并将飞船放到屏幕底部中央位置
        create_fleet(ai_settings,screen,ship,aliens)
        ship.center_ship(screen)

        # 暂停
        sleep(0.5)
    else:
        stats.game_active = False
        # 游戏结束时，显示鼠标
        pygame.mouse.set_visible(True)


def check_aliens_bottom(ai_settings,stats,screen,ship,aliens,bullets,sb):
    """检查是否有外星人到达了屏幕底端"""
    screen_rect = screen.get_rect()
    for alien in aliens.sprites():
        if alien.rect.bottom >= screen_rect.bottom:
            # 像飞船被撞一样进行处理
            ship_hit(ai_settings,stats,screen,ship,aliens,bullets,sb)
            break

def check_high_score(stats,sb):
    """检查是否诞生了新的最高得分"""
    if stats.score > stats.high_score:
        stats.high_score = stats.score
        sb.prep_high_score()
